Feature Request: Add progress arc behind slider controll

[ed-george]

If possible it would be great to see a solid color arc going from the top of the circle to the thumb control position to indicate the progress of the slider.

[milosmns]

There are other libraries that allow seeking. Since this is a slider, I'd like to recommend these ones as alternatives:

• https://github.com/carlosrobles/ArcSeekBar
• https://github.com/RaghavSood/AndroidCircularSeekBar
• https://github.com/neild001/SeekArc